Segment Information - Financial Information by Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Net sales	$ 1,017.2	$ 1,028.6
Segment income	180.8	183.6
Operating Segments
Segment Reporting Information [Line Items]
Net sales	1,017.2	1,028.6
Segment income	217.3	211.0
Water Solutions | Operating Segments
Segment Reporting Information [Line Items]
Net sales	273.1	272.0
Segment income	55.6	52.4
Other | Operating Segments
Segment Reporting Information [Line Items]
Net sales	0.3	0.5
Segment income	(26.4)	(22.6)
Pool | Operating Segments
Segment Reporting Information [Line Items]
Net sales	359.5	364.3
Segment income	110.8	116.2
Flow | Operating Segments
Segment Reporting Information [Line Items]
Net sales	384.3	391.8
Segment income	$ 77.3	$ 65.0